Concrete slab structure



Aug. 9? ima. J. W. WLCOTT 2,126,301

` CONCRETE SLAB STRCTURE Filed March 15, 1937 2 Sheets-Sheet l ug- 9, 1938 J. W. woLcoJ-T CONCRETE SLAB STRUCTURE Filed March l5, 1957 2 Sheets-Sheet 2 Patented Aug. 9,Y 1938 UNiTED STATES PATENT orFicE Application March 15,

4 Claims.

This invention relates to a hollow re-enforced concrete slab structure and to the method of making the same. rI'he slabs are designed to be used as pre-fabricated units in the construction 5 of floors, walls, partitions and roofs of buildings. They may be made of floor width and full story height and are particularly adapted for use in the construction of low-cost houses. The slabs may be cast with openings for doors or windows and with various fittings embedded in the slabs, but for the purpose of illustration, I have shown` in the drawings a plain slab without appurtenances.

The concrete which I prefer to use consists of Portland cement, sharp sand and an exploded blast furnace slag aggregate. In carrying out the invention, I rst cast a number of concrete channel-shaped members having flanges at their sides and ends, these members being relatively long and narrow, the length being dependent upon that of the slab to be produced. These are allowed to set sufficiently so that they can be handled without breakage but preferably not until they become completely seasoned and hardened. A layer of the concrete is then spread upon a plate, with a re-enforced metal fabric embedded in the layer. Adjustable form members on the plate define the boundaries of the layer, which forms one wall of the finished slab. The concrete is vibrated by vibrating the plate and then the channel members are laid on the concrete layer parallel with one another and spaced apart, and with their flanges extended downwardly. These channel members are pushed downwardly into the concrete until the flanges rest on the re-enforcing fabric. The channel members project above the concrete layer and form hollow spaces in the finished slab. Concrete is then filled into the spaces between the adjacent channel members and in the space be- 4.0` tween the group of channel members and the form members, and metal re-enforcing rods are arranged in these spaces, the concrete and reenforcing rods forming beams between the channel members and a continuous beam around the channel members. A layer of concrete is spread over the channel members and the beams and a metal re-enforcing fabric is embedded in this layer which forms a wall of the finished product.

^ After the concrete has been poured, it is vibrated and then allowed to set until it becomes hard. In setting, the poured concrete bonds with the concrete channel members making a one-piece concrete slab. The width of the beams can be adjusted to suit the load to be carried on any part of the slab by suitably spacing the channel memf 1937, Serial No. 131,044

(Cl. Y2- 66) bers in forming the slab, and where a beam is made wide, the number of re-enforcing rods for that beam is increased to sustain the load.

In the accompanying drawings,

Fig. l is a plan View of a slab made in accordance with my invention, the channel members beingV indicated in dotted lines;

Fig. 2 is a transverse section through the same on the line 2-2 of Fig. 1;

Fig. 3 is a perspective view of one of the preformed channel members, partly broken away;

Fig. 4 is a central longitudinal section through the same;

Fig. 5 is a view illustrating one step in the formation of the slab;

Fig. 6 is a similar View illustrating a succeeding step, the pre-formed channel members being shown in section;

Fig. 7 is a similar view illustrating the final step in forming the slab, and,

Fig. 8 is a plan view, on a small scale, showing the plate and form pieces upon which the slabs are cast. v

'I'he method of forming a slab A, shown in Figs. l and 2 of the drawings, is illustrated in Figs. 3 to 8, inclusive. Referring to the latter figures, channel members b of concrete, Figs. 3 and 4, are `first formed in suitable collapsible or otherwise removable molds-and these members are allowed to set until they can be handled without breakage, but preferably not until they have fully set and hardened. Each channel member comprises a relatively flat body portion I with parallel side ilanges 2 and end flanges 3, these flanges extending at the same side of the body portion and at a right angle thereto, the depth of the flanges depending upon the thickness of the slab tobe produced and the length ofthe members depending upon the length of the slab. As illustrated in Fig. 5v, a layer of concrete 4 is laid upon a ilat plate 5 with a metal re-enforcing fabric S embedded in the layer. This layer is laid between adjustable metal form pieces l, 8, 9 and lil which define the length and width of the slab, and the height of the form pieces cor responds with the thickness of the slab to be produced. This layer of concrete is vibrated, by vibrating the plate 5, until the concrete has the consistency of a thick jelly and some dampness begins to show on its surface. A number of the channel members are then laid parallel with one another on the concrete layer 4 with the open sides of the members facing downward and the members are pressed into the soft concrete until they engage the re-enforcing fabric as shown in Fig. 6. Concrete is then filled into the spaces Il between the adjacent channel members and into the spaces I2 between the group of members and the form pieces "I, 8, 9 and I0, as shown in Fig. 7. Metal re-enforcing rods I3 which surround the group of channel members are arranged in the spaces I2 and embedded in the concrete as shown in Fig. 7 and metal re-enforcing rods I4 are arranged longitudinally in the spaces II and embedded in the concrete asshown in said figure. A concrete layer covers the channel members, a re-enforcing fabric I5 is laid on this layer and a finishing layer covers the fabric which becomes embedded in the slab. The concrete, after being Vibrated, is leveled off even with the tops of the form pieces, either with a rough or smooth surface, as desired, and allowed to set, and the completed slab can then be removed from the supporting plate by removing the form pieces.

The poured concrete in which the pre-formed concrete channel members become embedded bonds with the latter, forming a one-piece concrete structure. This bonding is more perfect if the channel members are incorporated in the slab before they become completely seasoned and hard. Preferably the outer surfaces of the 'channel members are scored or roughened to cause the poured concrete to inter-lock mechanically with the channel members.

In the completed slab the walls a.1 and a2, spaced apart by the channel members, are connected together between such members by longitudinal re-v enforced concrete beams as, cL1 etc., Fig. 7, between the members and by a continuous re-enforced concrete beam c which extends around the margin of the slab.

The width of the beams a, a, etc., is determined by the spacing of the pre-formed channel members. Channel members of any desired width may be used and they may be set closer to or farther from one another to vary the width of the beams. Thus in Figs. 1 and 2 of the drawings, the beam d,5 is shown of greater width than the other beams and with a greater number of reenforcing rods I4. Where one part of a slab has to carry a greater weight than other portions, the beam or beams at that part will be wider and will carry a greater number of re-enforcmg rods than other beams, where the load to be carried is lighter. If, for instance, in a building structure, a partition is to rest on a certain part of a floor slab, the slab can be cast with a stronger beam or beams at that part by suitably spacing the preformed channel members and supplying additional re-enforcing rods in the space or spaces between the members. Likewise the marginal beam c may be made of any desired width by using con` crete channel members of appropriate length and width and adjusting them with respect to the form pieces, and additional re-enforcing members can be supplied as the beam is widened.

The slabs will usually be formed at their edges to inter-fit with other slabs ori to receive devices for connecting them to other slabs or parts, for quick assembly in erecting a building; but such are not shown in the drawings. Also, the channel members need not be made entirely of concrete. For ease in handling without breakage, they may be made in part of suitable 13e-enforcing material.

What I claim is:

1. A pre-formed building slab comprising a wall of concrete having a layer of re-enforcing material embedded therein, a group of oblong pre-formed concrete channel members, each having side and end flanges, said members arranged parallel with one another and spaced apart and having their flanges embedded in said wall, a concrete filling between said members and surrounding the group of members, forming beams between said members and surrounding the group of members, and extending over the outer' sides of said members and beams, forming a Wall, a layer of re-enforcing material in the latter wall, and re-enforcing rods extending longitudinally through said beams.

2. A pre-formed building slab comprising a wall of concrete having a layer of re-enforcing material embedded therein, a group of oblong preformed concrete channel members each having side and end flanges, said members arranged parallel with one another and spaced apart and having their flanges embedded in said wall and engaging said re-enforcing material, a concrete filling between said members and surrounding the group of members, forming beams between said members and surrounding the group of members, and extending over the outer sides of said members and beams, forming a wall, a layer of reenforcing material in the latter wall, and reenforcing rods extending longitudinally through said beams.

3. The method of making a hollow concrete building slab which comprises forming a plurality of oblong concrete channel members having side and end flanges, placing a layer of concrete on a relatively flat support to form a wall and embedding a layer of re-enforcing material in said layer of concrete, placing said channel members side by side and spaced apart over said layer of concrete with the flanges of said members embedded therein before said channel members have become completely hardened, and, before said members have completely hardened, placing concrete between said members and around the group of members, forming beams, and over said members and beams, forming a wall, and embedding re-enforcing members in said latter wall and beams.

4. The method of making a hollow concrete building slab which comprises forming a plurality of oblong concrete channel members having side and end flanges, placing a layer of concrete on a relatively flat support to form a wall and embedding a layer of re-enforcing material in said layer of concrete, placing said channel members side by side and spaced apart over said layer of concrete with the flanges of said members embedded therein and resting on said re-enforcing material before said channel members have become completely hardened, and, before said members have completely hardened, placing concrete between said members and around the group of members, forming beams, and over Said members and beams, forming a wall, and embedding reenforcing members in said latter wall and beams.

JOI-IN WINTHROP WOLCOTT. 

